1. Technical Field
The present invention relates to an apparatus for helping to protect an occupant of a vehicle, and relates particularly to an apparatus including a knee bolster movable from a stored position to a blocking position.
2. Description of the Prior Art
Actuatable vehicle occupant knee bolsters are known in the art. Such a knee bolster is located at a lower portion of a vehicle instrument panel and is movable from a stored position to a blocking position in response to detection of a vehicle crash condition. The knee bolster can help to prevent the vehicle occupant from "submarining" underneath an inflated air bag. Knee bolster systems have been developed that use an inflatable device, such as an air bag, for moving the knee bolster.
Also known in the art is a device known as a pyrotechnic transfer line, or gas generating linear pyrotechnic element. This device is an elongate assembly comprising three strands of glass fiber that are impregnated with an explosive material and enclosed in a plastic sleeve. It is known to use a pyrotechnic transfer line as an ignition device, or fuse, for an actuatable device such as an air bag inflator. It is also known to use a pyrotechnic transfer line as a gas generating device for a pretensioner or a side curtain. Such uses are shown in U.S. Pat. Nos. 5,145,209 and 5,755,457.